Serum lipid and lipoprotein studies will be conducted on mice with free cholesterol storage disease and compared to non-affected colony mice from free cholesterol storage disease carriers and out of colony control animals. Serum lipoproteins will be isolated and characterized as regards their protein and lipid content, analytical ultracentrifuge behavior, gel filtration chromatography properties, and agarose gel electrophoretic mobility. Selected tissues will be studied for their cholesterol and lipid content and pathologic involvement in the same groups of animals. Tissue sterols of some tissues will be separated by multiple thin layer chromatography and evaluated for non-cholesterol sterol content by mass spectrometer-gas liquid chromatography. Fractionation of liver subcellular organelles by density gradient ultracentrifugation will be carried out. The cholesterol and protein content, organelle enzyme activity patterns, and electron microscopic evaluation for purity will be conducted on the purified fractions.